Bitrate control device, bitrate control method, and computer program

Abstract

To provide a bit rate control device capable of maintaining the quality of relatively important video data even when communication conditions deteriorate.SOLUTION: A bit rate control device includes statistical information acquisition means for acquiring statistical information relating to network communications, configuration information acquisition means for acquiring tally information indicating the output status of a plurality of pieces of video data, bit rate determination means for determining an encoding bit rate on the basis of the statistical information and the tally information, and bit rate control means for changing the encoding bit rate to the determined bit rate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bit rate control device, a bit rate control method, a computer program, and the like. [Background technology]

[0002] An increasing number of video devices are capable of transmitting video and audio over IP networks (IP streaming), but unlike conventional technologies such as SDI and HDMI (registered trademark), IP networks require bandwidth management and are used on a best-effort basis.

[0003] For this reason, adaptive bitrate streaming (ABR) is a technology used in IP streaming that changes the streaming bitrate of the camera depending on the communication conditions between the transmitter (camera) and receiver. By using ABR, the transfer rate can be dynamically controlled according to the network conditions, allowing for continuous streaming without image distortion or long pauses.

[0004] One way to achieve ABR is to utilize network statistics. For example, SRT (Secure Reliable Transport), a video transmission protocol, is characterized by high safety, reliability, and connectivity, and one of the mechanisms that supports these is the ability to obtain network statistics.

[0005] Meanwhile, switchers for selecting and distributing video from multiple cameras are also becoming IP-compatible, but when multiple cameras and switchers are connected within the same network, the streaming bitrate must be determined carefully.

[0006] Here, the switcher controls the camera tally, which displays the lamps and UI to indicate the camera status to the cameraman and performer, and many of them have means to send status signals and information such as whether the camera is streaming or on standby.

[0007] For example, in Patent Document 1, the bit rate is changed according to a bit rate command value calculated by the transmitting device depending on the TCP throughput between the transmitting device connected to the camera and the receiving device to which the transmitting device delivers video, thereby preventing interruptions in video delivery from the transmitting device. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-102866 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in Patent Document 1, in a distribution system configured with a plurality of cameras and a switcher each having an ABR IP streaming function, there are cases where images from a plurality of cameras on the same network are distributed via the switcher.

[0010] In such cases, if bandwidth restrictions are imposed due to a deterioration in communication conditions, the bitrate of the camera capturing important footage (for example, the camera currently streaming) may be reduced along with the other cameras, which may result in a decrease in the quality of the footage captured by the important camera.

[0011] One of the objects of the invention of this application is to provide a bit rate control device that can maintain the quality of relatively important video data even when communication conditions deteriorate. [Means for solving the problem]

[0012] A bit rate control device according to one aspect of the present invention comprises: The system is characterized by having a statistical information acquisition means for acquiring statistical information regarding network communications, a configuration information acquisition means for acquiring tally information indicating the output status of multiple pieces of video data, a bit rate determination means for determining an encoding bit rate based on the statistical information and the tally information, and a bit rate control means for changing the encoding bit rate to the determined bit rate. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a bit rate control device that can maintain the quality of relatively important video data even when the communication conditions deteriorate. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating an example of a network configuration according to a first embodiment of the present invention. [Figure 2] 1 is a functional block diagram showing an example of the configuration of a camera 100 according to a first embodiment. [Figure 3] 1 is a functional block diagram showing an example of the configuration of a switcher 200 according to a first embodiment. [Figure 4A] 4 is a flowchart showing an example of processing performed by the camera 100 according to the first embodiment. [Figure 4B] 4B is a flowchart showing an example of processing following FIG. 4A. [Figure 5] 4 is a flowchart showing an example of processing by the switcher 200 according to the first embodiment. [Figure 6] FIG. 10 is a functional block diagram showing an example of the configuration of a camera 100 according to a second embodiment. [Figure 7] FIG. 10 is a functional block diagram showing an example of the configuration of a switcher 200 according to a second embodiment. [Figure 8] 10 is a flowchart showing an example of a bit rate control method performed by the camera 100 according to the second embodiment. [Figure 9A] 10 is a flowchart showing an example of processing by the switcher 200 according to the second embodiment. [Figure 9B]9B is a flowchart showing an example of processing continued from FIG. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. In each drawing, the same members or elements are designated by the same reference numerals, and duplicate descriptions will be omitted or simplified.

[0016] <Embodiment 1> 1 is a diagram showing an example of the network configuration of a camera system 1000 according to a first embodiment of the present invention. The camera system 1000 in this embodiment functions as a bit rate control device, and is made up of a plurality of cameras 100, a switcher 200, a router or switching hub 300, a client device 400, a monitor 500, etc.

[0017] As described above, the camera system 1000 serving as the bit rate control device of this embodiment includes a plurality of cameras 100 serving as a plurality of video output devices that output video data, and the switcher 200.

[0018] Video data from multiple cameras 100 is sent to switcher 200 via router or switching hub 300, and the video selected by switcher 200 is displayed on monitor 500. In other words, switcher 200 has the function of switching video data from multiple video output devices, and can distribute the data to client device 400, which is an external device (such as a PC), via network switch (router / switching hub) 300.

[0019] The camera 100 as a video output device may be a still camera or video camera that mainly has a photographing function, a camera-equipped mobile phone, a tablet terminal, a security camera, etc. The video output device may also be a recording / playback device that records and plays back video and outputs the video data.

[0020] Fig. 2 is a functional block diagram showing an example of the configuration of the camera 100 according to the embodiment 1. Note that some of the functional blocks shown in Fig. 2 are realized by causing a CPU or the like serving as a computer included in the camera 100 or the like to execute a computer program stored in a memory serving as a storage medium.

[0021] However, some or all of these functions may be implemented by hardware, which may be a dedicated circuit (ASIC) or a processor (reconfigurable processor, DSP).

[0022] Furthermore, the functional blocks shown in Fig. 2 do not have to be built into the same housing, but may be configured as separate devices connected to each other via signal paths. The above explanation regarding Fig. 2 also applies to Figs. 3, 6, and 7.

[0023] In the camera 100 of FIG. 2, a CPU 201 as a computer, a volatile memory 202, a nonvolatile memory 203, an output processing unit 204, an input processing unit 205, a communication control unit 208, and a camera signal processing unit 212 are connected to an internal bus 207.

[0024] Furthermore, a communication statistics acquisition unit 214, a configuration information acquisition unit 215, a bit rate control unit 216, a bit rate determination unit 217, and an encoding / decoding processing unit 218 are connected to the internal bus 207. The units connected to the internal bus 207 are capable of exchanging data with each other via the internal bus 207.

[0025] The volatile memory 202 stores computer programs, variables, temporary work data, and the like required by the CPU 201 during operation. The non-volatile memory 203 is configured with a flash memory or the like, and stores various computer programs required for the operation of the CPU 201. The CPU 201 also controls each unit of the camera 100 in accordance with the computer programs stored in the non-volatile memory 203, using the volatile memory 202 as a work memory.

[0026] The optical system 210 is a group of photographic lenses including focus and aperture mechanisms, and forms an optical image of a subject on the light receiving surface of the image sensor 211. The image sensor 211 is composed of a CCD, CMOS element, or the like, and includes an A / D converter in this case, which converts the optical image into an analog signal and then into a digital signal.

[0027] Under the control of the CPU 201, the camera signal processing unit 212 performs predetermined pixel interpolation, resizing such as reduction, color conversion, various correction processes, and the like on the digital signal converted by the image sensor 211.

[0028] A communication control unit 208 communicates with the switcher 200 via a connector (wired) / antenna (wireless) 209 under the control of the CPU 201. As a communication method, wireless IEEE802.11 or Bluetooth, wired IEEE802.3, or the like can be used.

[0029] The encoding / decoding processing unit 218 compresses and encodes the digital signal processed by the camera signal processing unit 212 in a predetermined format at a predetermined bit rate under the control of the CPU 201. It also decodes the compressed and encoded data.

[0030] Although audio is not specifically shown, when distributing video with audio, the system is configured to include a microphone, an A / D converter that digitizes the analog audio signal, and a device that encodes the digital data. When recording video, audio is also recorded simultaneously with the video, and the video and audio are multiplexed in the encoding / decoding processor 218 to generate video data with audio.

[0031] The communication statistics acquisition unit 214 stores information such as the bit rate, number of packets, and number of retransmitted packets of data sent and received by the communication control unit 208 in the volatile memory 202 as statistical information, and reads out the statistical information when an acquisition request is made.

[0032] In this way, the statistical information includes at least one of the available bandwidth of the network and the number of retransmitted packets. Here, the communication statistics acquisition unit 214 functions as a statistical information acquisition means for acquiring statistical information related to network communications.

[0033] Based on the control of the CPU 201, the configuration information acquisition unit 215 analyzes information about the network configuration from the data sent and received by the communication control unit 208, stores it in the volatile memory 202, and reads out the configuration information when an acquisition request is made.

[0034] Here, the configuration information acquisition unit 215 functions as a configuration information acquisition means for acquiring tally information indicating the output status of multiple video data. Note that the tally information is tally information indicating the output status of video output devices connected to the network.

[0035] The bit rate determination unit 217 acquires communication statistical information from the communication statistical acquisition unit 214 and configuration information from the configuration information acquisition unit 215 under the control of the CPU 201, and determines an appropriate compression encoding bit rate from the acquired information. Here, the bit rate determination unit 217 functions as a bit rate determination means that determines an encoding bit rate based on the statistical information and configuration information.

[0036] Under the control of the CPU 201, the bit rate control unit 216 controls and sets the bit rate determined by the bit rate determination unit 217 as a predetermined value for the compression encoding bit rate of the encoding / decoding processing unit 218. Here, the bit rate control unit 216 functions as bit rate control means that determines the encoding bit rate based on the statistical information and tally information.

[0037] The input processing unit 205 receives user operations via the operation unit 206, generates control signals corresponding to the operations, and supplies them to the CPU 201. The operation unit 206 is an input device that receives user operations, and includes a zoom operation lever, a character information input device such as a keyboard, a pointing device such as a mouse or a touch panel, and a remotely operable device such as an infrared remote control.

[0038] The touch panel is an input device that outputs coordinate information according to the position of contact on an input unit configured, for example, as a flat surface, and can cause the camera 100 to perform operations according to user operations.

[0039] The output processing unit 204 outputs a display signal for causing the display unit 213 to display, based on display data such as a GUI (Graphical User Interface) generated by the CPU 201 in accordance with a program.

[0040] When a touch panel is used as the operation unit 206, the operation unit 206 and the display unit 213 can be integrally configured. For example, the touch panel is configured so that the light transmittance does not interfere with the display of the display unit 213, and is attached to the upper layer of the display surface of the display unit 213.

[0041] Then, input coordinates on the touch panel are associated with display coordinates on the display unit 213, thereby forming a GUI that allows the user to directly operate the screen displayed on the display unit 213.

[0042] Fig. 3 is a functional block diagram showing an example of the configuration of the switcher 200 according to embodiment 1. In the switcher 200 in Fig. 3, 301 to 309 and 318 are functional blocks similar to 201 to 209 and 218 of the camera 100, respectively, and therefore a description thereof will be omitted.

[0043] The encoding / decoding processing unit 318 decodes the compressed video data and re-encodes the decoded data as necessary under the control of the CPU 301. The CPU 301 also controls each unit of the switcher 200 in accordance with a computer program stored in the nonvolatile memory 303, using the volatile memory 302 as a work memory.

[0044] A bit rate control device and a bit rate control method according to a first embodiment of the present invention will be described below with reference to Figures 1 to 5. In the first embodiment, a camera 100 functions as a bit rate control device, and the camera 100 executes the bit rate control method.

[0045] Fig. 4A is a flowchart showing an example of processing by the camera 100 according to the first embodiment, and Fig. 4B is a flowchart showing a continuation of the processing example shown in Fig. 4A. The CPU 601, which serves as a computer within the camera 100, executes a computer program stored in memory, thereby sequentially performing the operations of the steps in the flowcharts of Fig. 4A and Fig. 4B.

[0046] When the user designates the switcher 200 as the destination of the IP streaming from the operation unit 206 of the camera 100 and executes the IP streaming at the bit rate set by the user, the flow of FIG. 4A starts.

[0047] In step S401, a network connection with the switcher 200, which is an external device, is established in accordance with the settings under the control of the CPU 201. In step S402, the video data compression-encoded by the encoding / decoding processing unit 218 is transmitted by the communication control unit 208 to the switcher 200 as the destination.

[0048] Furthermore, the switcher 200, which is the destination of the transmission, transmits to the camera 100, which is the source of the transmission, the number of cameras connected to the switcher 200, the total bit rate value (total bit rate), etc. as configuration information periodically or when an information update occurs.

[0049] Furthermore, the switcher 200 transmits tally information indicating the video data output status of multiple cameras connected to the network, the bit rate for each video data output status determined by the bit rate determination unit 217, and the like as configuration information periodically or when an information update occurs.

[0050] In step S403, the communication statistics acquisition unit 214 acquires the available bandwidth from the statistical information, and the configuration information acquisition unit 215 acquires the current total bit rate from the configuration information. Here, step S403 functions as a statistical information acquisition step for acquiring statistical information related to network communications, and a configuration information acquisition step for acquiring tally information indicating the output status of multiple video data.

[0051] In step S404, the current total bit rate acquired in step S403 is compared with the available bandwidth to determine whether the total bit rate exceeds the available bandwidth. If the current total bit rate exceeds the available bandwidth, the process proceeds to step S405; if not, the process proceeds to step S406.

[0052] In step S405, the configuration information acquisition unit 215 acquires tally information and camera number information from the configuration information, and the process proceeds to step S407. Meanwhile, in step S406, the bit rate determination unit 217 determines the encoding bit rate to be the bit rate set by the user, the bit rate control unit 216 sets the determined encoding bit rate in the encoding / decoding processing unit 218, and the process proceeds to step S412.

[0053] In step S407, the type of tally information of the video output data transmitted from the switcher is determined. If the tally information indicates that distribution is in progress, the process proceeds to step S408. If the tally information indicates that distribution is in progress, the process proceeds to step S409. If the tally information is neither distribution nor standby, the process proceeds to step S410.

[0054] In step S408, the bit rate during distribution is determined by the bit rate determination unit 217. Note that the bit rate determination unit 217 is set in advance so that the weight of the bit rate during distribution is the highest.

[0055] In this way, in this embodiment, a high bit rate is assigned to video data with a high priority (importance) based on tally information indicating the output status of multiple video data (types such as currently being distributed, waiting, other, etc.).

[0056] Also, the weight of the bit rate during standby is set to be smaller than the weight of the bit rate during streaming, and larger than the weight of the bit rate other than streaming or standby, or equal to the weight of the bit rate other than streaming or standby. Note that here, the weight is set assuming that the video being streamed is the most important, but the weight may be changed depending on the importance of the video data output state.

[0057] In this manner, in this embodiment, a higher bit rate is assigned to video data when the tally information indicates that the data is being distributed than to video data that is not being distributed. Also, a higher bit rate is assigned to video data when the tally information indicates that the data is being distributed than to video data that is waiting to be distributed. Also, a bit rate equal to or higher than that of video data that is neither being distributed nor waiting to be distributed is assigned to video data when the tally information indicates that the data is waiting to be distributed.

[0058] In step S408, the bit rate determination unit determines the bit rate using the following formula 1 based on the above bit rate weight, the available bandwidth acquired by the communication statistics acquisition unit, and the number of cameras connected to the switcher 200 acquired by the configuration information acquisition unit. (Bit rate) = (Available bandwidth) × (Bit rate weight) / (Number of cameras) (Equation 1)

[0059] In step S409, the standby bit rate is determined by the bit rate determination unit 217. That is, the bit rate is determined using the weighting of the standby bit rate determined by the bit rate determination unit 217 and equation 1, as in step S408.

[0060] In step S410, the bit rate determination unit 217 determines the bit rate for periods other than distribution and standby. That is, the bit rate is determined using Equation 1, as in step S408, using the weighting of the bit rate for periods other than distribution and standby determined by the bit rate determination unit 217. In this way, steps S408 to S410 function as bit rate determination steps that determine the encoding bit rate based on the statistical information and tally information.

[0061] In step S411, the bit rate control unit 216 sets the coding bit rate determined in steps S408 to S410 in the encoding / decoding processing unit 218. Here, step S411 functions as a bit rate control step for changing the coding bit rate to the determined bit rate.

[0062] In step S412, it is determined whether the network has been disconnected or the transmission of video data has ended. That is, it is determined whether the user has terminated the transmission of video data using the operation unit 206 of the camera 100, or has disconnected the network connection with the switcher 200 using the operation unit 206, or has disconnected the network connection with the camera using the operation unit 306 of the switcher 200.

[0063] 4A and 4B ends if it is determined as Yes in step S412, and returns to step S402 if it is determined as No in step S412. In this way, in this embodiment, the change in the bit rate is controlled based on the result of comparing the current total bit rate with the available bandwidth.

[0064] Moreover, when the current total bit rate becomes larger than the available bandwidth, the bit rate is changed, and when the current total bit rate becomes smaller than the available bandwidth, the bit rate is set to a predetermined value.

[0065] In this embodiment, the available bandwidth is obtained from the statistical information and the current total bit rate is obtained from the configuration information in step S403, and it is determined in step S404 whether the current total bit rate exceeds the available bandwidth.

[0066] However, it is also possible to have the communication statistics acquisition unit 214 acquire only the available bandwidth and current bit rate of the camera 100 alone and determine whether the current bit rate exceeds the available bandwidth. In this case, in step S408, if the tally information of the video data output is being distributed, the current bit rate is maintained, and in step S409, the current bit rate is reduced.

[0067] Additionally, the bit rate for times other than when distribution is in progress is set to a value greater than 0 or to 0. However, if the available bandwidth increases by lowering the bit rate for times other than when distribution is in progress, the bit rate for times other than when distribution is in progress may be set to the highest possible bit rate within the available bandwidth while maintaining the bit rate for times during distribution.

[0068] The camera that is currently distributing continues to check whether the bit rate exceeds the available bandwidth until the network is disconnected or the transmission of the video data is not completed. If the bit rate of the camera that is currently distributing exceeds the available bandwidth even after a predetermined time has passed, the current bit rate is gradually reduced to a bit rate that falls within the available bandwidth.

[0069] In the above example, the bit rate determination unit 217 changes the bit rate in accordance with the predetermined bit rate weights in steps S408, S409, and S410. However, the user may set the bit rate weights (allocations) for each state of the tally information from the operation unit 206, and the bit rate may be changed in accordance with the set values.

[0070] Fig. 5 is a flowchart showing an example of processing by the switcher 200 according to embodiment 1. Note that the CPU 501 serving as a computer within the switcher 200 executes a computer program stored in memory, thereby sequentially performing the operations of the steps in the flowchart of Fig. 5.

[0071] In step S501, it is determined whether there is a change in the number of cameras connected to the switcher 200, such as whether there is a new camera that is about to be connected to the switcher 200, or whether there is a camera that is already connected to the switcher 200 that is to be disconnected. If there is a change in the number of connected cameras, the process proceeds to step S502, and if there is no change in the number of connected cameras, the process proceeds to step S503.

[0072] In step S502, if there is a new camera attempting to connect to the switcher 200, the communication control unit 308 starts receiving the video data compressed and encoded by the camera 100.

[0073] If the number of connected cameras decreases, for example, if a camera 100 that is already connected to the switcher 200 is disconnected, the reception of video data from the camera 100 that has been disconnected from the switcher 200 is terminated under the control of the CPU 301. After step S502, the process proceeds to step S504.

[0074] On the other hand, in step S503, the communication control unit 308 receives the compressed and encoded video data from the connected camera 100. Then, the process proceeds to step S504.

[0075] In step S504, the configuration information and statistical information such as the available bandwidth and the number of retransmitted packets are updated periodically or when a difference of a predetermined value or more occurs in the information. In this manner, in this embodiment, the tally information or statistical information is updated periodically or when a difference of a predetermined value or more occurs in the tally information or statistical information.

[0076] The configuration information includes the number of cameras connected to the switcher 200, the total bit rate (total bit rate), tally information indicating the video data output (selection) status of multiple cameras connected to the network, and the bit rate for each video data output status determined by the camera.

[0077] That is, the configuration information acquisition means in this embodiment acquires at least one of information indicating the number of video output devices connected to the switcher, information indicating the total value of the bit rates of multiple video data, and tally information indicating the output states of the video output devices connected to the network. The configuration information acquisition means may also include information indicating the bit rate for each video data output state determined by the video output device.

[0078] In step S505, update information for the configuration information and statistical information is sent to the camera 100 via the communication control unit 308. In step S506, it is determined whether the user has disconnected the network connection with the camera using the operation unit 306. If the network has not been disconnected, the process returns to step S501; if the network has been disconnected, the flow in FIG. 5 ends.

[0079] <Embodiment 2> Next, a description will be given of embodiment 2. Note that the network configuration example of embodiment 2 is the same as that of embodiment 1, and therefore the description will be omitted.

[0080] Fig. 6 is a functional block diagram showing an example of the configuration of a camera 100 according to embodiment 2. In the camera 100 of Fig. 6, 601 to 613 and 618 are functional blocks similar to 201 to 213 and 218 of the camera 100 of Fig. 2, respectively, and therefore description thereof will be omitted.

[0081] Fig. 7 is a functional block diagram showing an example of the configuration of a switcher 200 according to embodiment 2. In the switcher 200 in Fig. 7, 701 to 709 and 714 to 718 are similar to the functional blocks 201 to 209 and 214 to 218 of the camera 100 in Fig. 2, and therefore description thereof will be omitted.

[0082] A bit rate control device and a bit rate control method according to a second embodiment of the present invention will be described below.

[0083] Fig. 8 is a flowchart showing an example of a bit rate control method by the camera 100 according to embodiment 2. Note that the CPU 601, which serves as a computer within the camera 100, executes a computer program stored in memory, thereby sequentially performing the operations of the steps in the flowchart of Fig. 8.

[0084] 8 starts when the user specifies the destination of the IP streaming from the operation unit 606 of the switcher 200 and executes IP streaming at the bit rate set by the user on the camera 100. In step S801, under the control of the CPU 601, a connection is made to the camera 100 and the network in accordance with the settings.

[0085] In step S802, the video data compression-encoded by the encoding / decoding processing unit 618 is transmitted to the destination by the communication control unit 608. In step S803, the communication control unit 608 determines whether or not the changed encoding bit rate has been received. If it has been received, the process proceeds to step S804; if it has not been received, the process proceeds to step S805.

[0086] In step S804, the received changed encoding bit rate is set in the encoding / decoding processing unit 618. In step S805, it is determined whether the network connection with the camera has been disconnected by an operation of the camera 100 or the switcher 200, or whether transmission of video data has been terminated by an operation of the camera 100.

[0087] If the answer to step S805 is YES, the flow of Fig. 8 ends. On the other hand, if the network is disconnected or the transmission of the video data is not completed, the flow returns to step S802.

[0088] Fig. 9A is a flowchart showing an example of processing by the switcher 200 according to the second embodiment, and Fig. 9B is a flowchart showing a continuation of the processing example shown in Fig. 9A. Note that the CPU 701, which serves as a computer within the switcher 200, executes a computer program stored in memory, thereby sequentially performing the operations of the steps in the flowcharts of Fig. 9A and Fig. 9B. The following description follows this flow.

[0089] In step S901, the CPU 701 determines whether there is a change in the number of cameras connected to the switcher 200, such as whether there is a new camera that is attempting to connect to the switcher 200, or whether there is a camera that is already connected to the switcher 200 that is to be disconnected.

[0090] If there is a change in the number of connected cameras, the process proceeds to step S902, and if there is no change in the number of connected cameras, the process proceeds to step S903. In step S902, if a new camera attempts to connect to the switcher 200, the communication control unit 708 starts receiving the video data compressed and encoded by the camera 100.

[0091] If the number of connected cameras decreases, for example, if a camera already connected to the switcher 200 is disconnected, the CPU 701 controls to terminate reception of video data from the camera 100 that has been disconnected from the switcher 200. Then, the process proceeds to step S904.

[0092] On the other hand, in step S903, the communication control unit 708 receives the compressed and encoded video data from the connected camera 100. Then, the process proceeds to step S904.

[0093] In step S904, the configuration information and statistical information such as the available bandwidth and the number of retransmitted packets are updated periodically or when a difference occurs in the information. The configuration information in this embodiment includes at least one of the following pieces of information.

[0094] That is, the configuration information includes at least one of the number of cameras connected to the switcher 200, the total value of the bit rate (total bit rate), and tally information indicating the video data output (selection) state of multiple cameras connected to the network. Alternatively, the configuration information may include the bit rate for each video data output state determined by the camera 100.

[0095] In step S905, the communication statistics acquisition unit 714 acquires the available bandwidth from the statistical information, and the configuration information acquisition unit 715 acquires the current total bit rate from the configuration information.

[0096] In step S906, it is determined whether the current total bit rate acquired in step S905 exceeds the available bandwidth. If the determination in step S906 is Yes, the process proceeds to step S907, and if the determination is No, the process proceeds to step S908.

[0097] In step S907, the configuration information acquisition unit 715 acquires tally information and the number of cameras from the configuration information. Meanwhile, in step S908, the bit rate determination unit 717 determines the encoding bit rate to be the bit rate set by the user, and the bit rate control unit 716 sets the determined encoding bit rate in the encoding / decoding processing unit 718.

[0098] In step S909, the type of tally information of the video output data transmitted from the switcher is determined. If the tally information indicates that distribution is in progress, the process proceeds to step S910. If the tally information indicates that distribution is in progress, the process proceeds to step S911. If the tally information is neither distribution nor standby, the process proceeds to step S912.

[0099] In step S910, the bit rate during distribution is determined by the bit rate determination unit 717. The bit rate determination unit 717 is set in advance so that the weight of the bit rate during distribution is the highest.

[0100] Also, the weight of the bit rate during standby is set to be smaller than the weight of the bit rate during streaming, and larger than the weight of the bit rate other than streaming or standby, or equal to the weight of the bit rate other than streaming or standby. Note that here, the weight is set assuming that the video being streamed is the most important, but the weight may be changed depending on the importance of the video data output state.

[0101] That is, in step S910, the bit rate is determined using the above-mentioned formula 1 based on the bit rate weight, the available bandwidth of the statistical information acquired by the communication statistics acquisition unit 714, and the number of cameras connected to the switcher 200 acquired by the configuration information acquisition unit 715.

[0102] In step S911, the standby bit rate is determined by the bit rate determination unit 717. That is, the bit rate is determined using the weighting of the standby bit rate determined by the bit rate determination unit 717 and equation 1, as in step S910.

[0103] In step S912, the bit rate other than during distribution or standby is determined by the bit rate determination unit 717. That is, using the weighting of the bit rate other than during distribution or standby determined by the bit rate determination unit 717, the bit rate is determined using Equation 1 in the same way as in step S910.

[0104] In step S913, the encoding bit rate determined by the bit rate control unit 716 in steps S910 to S912 is transmitted to the camera 100 via the communication control unit 708.

[0105] In step S914, it is determined whether the user has disconnected the network connection with the camera using the operation unit 706. If the network connection has not been disconnected, the process returns to step S901. If the network connection has been disconnected, the flow of Figures 9A and 9B ends.

[0106] In steps S910 to S912 of this flow, the bit rate determination unit 717 changes the bit rate according to a predetermined weight. However, the user may set the weight (allocation) of each state bit rate of the tally information from the operation unit 706, and change the bit rate according to the set value.

[0107] In the above embodiment, the bit rate control means may change and control the bit rate in response to a command request from an external device. Also, when the current total bit rate is greater than the available bandwidth, the current bit rate may be maintained for video data currently being distributed, and the bit rate for video data waiting to be distributed may be reduced.

[0108] Alternatively, the user may predetermine the allocation of bit rates for video data currently being distributed or waiting to be distributed, and when the current bit rate becomes larger than the available bandwidth, the bit rate may be changed in accordance with the predetermine allocation.

[0109] The present invention has been described in detail above based on preferred embodiments, but the present invention is not limited to these specific embodiments, and various forms within the scope of the gist of the present invention are also included in the present invention. Parts of the above-described embodiments may be combined as appropriate. The present invention also includes the following combinations.

[0110] (Configuration 1) A bit rate control device comprising: a statistical information acquisition means for acquiring statistical information related to network communications; a configuration information acquisition means for acquiring tally information indicating the output status of multiple pieces of video data; a bit rate determination means for determining an encoding bit rate based on the statistical information and the tally information; and a bit rate control means for changing the encoding bit rate to the determined bit rate.

[0111] (Configuration 2) The bit rate control device according to configuration 1, characterized in that it includes a plurality of video output devices that output the video data.

[0112] (Configuration 3) The bit rate control device according to configuration 1 or 2, further comprising a switcher for switching between the plurality of video data.

[0113] (Configuration 4) A bit rate control device according to any one of configurations 1 to 3, characterized in that the bit rate determination means assigns a higher bit rate to the video data with a higher priority based on tally information indicating the output status of the plurality of video data.

[0114] (Configuration 5) The bit rate control device according to configuration 4, wherein the bit rate determination means allocates a higher bit rate to the video data when the tally information indicates that the video data is currently being distributed than to video data that is not currently being distributed.

[0115] (Configuration 6) The bit rate control device according to configuration 5, wherein the bit rate determination means allocates a higher bit rate to the video data when the tally information indicates that the video data is currently being distributed than to video data that is waiting to be distributed.

[0116] (Configuration 7) The bit rate control device according to Configuration 6, characterized in that the bit rate determination means assigns a bit rate to the video data when the tally information indicates that the video data is waiting to be distributed that is equal to or higher than that of video data that is neither being distributed nor waiting to be distributed.

[0117] (Configuration 8) The bit rate control device according to any one of configurations 1 to 7, wherein the statistical information includes at least one of the available bandwidth of the network and the number of retransmitted packets.

[0118] (Configuration 9) A bit rate control device according to configuration 8, wherein the bit rate determination means controls the change of the bit rate based on a result of comparing the current total bit rate with the available bandwidth.

[0119] (Configuration 10) A bit rate control device according to configuration 9, characterized in that the bit rate determination means changes the bit rate when the current total bit rate becomes larger than the available bandwidth, and sets the bit rate to a predetermined value when the current total bit rate becomes smaller than the available bandwidth.

[0120] (Configuration 11) A bit rate control device described in any one of configurations 1 to 10, characterized in that the tally information or the statistical information is updated periodically or when a difference of a predetermined value or more occurs in the tally information or the statistical information.

[0121] (Configuration 12) The bit rate control device according to any one of configurations 1 to 11, characterized in including a plurality of video output devices that output the plurality of video data, and a switcher that switches between the plurality of video data.

[0122] (Configuration 13) The bit rate control device according to any one of configurations 1 to 12, wherein the tally information is tally information indicating the output state of the video output device connected to the network.

[0123] (Configuration 14) The bit rate control device according to Configuration 12, characterized in that the configuration information acquisition means acquires at least one of information indicating the number of the video output devices connected to the switcher, information indicating the total value of the bit rates of the multiple video data, the tally information indicating the output status of the video output devices connected to the network, and information indicating the bit rate for each video data output status determined by the video output device.

[0124] (Method) A bit rate control method characterized by comprising: a statistical information acquisition step of acquiring statistical information related to network communications; a configuration information acquisition step of acquiring tally information indicating the output status of multiple pieces of video data; a bit rate determination step of determining an encoding bit rate based on the statistical information and the tally information; and a bit rate control step of changing the encoding bit rate to the determined bit rate.

[0125] (Program) A computer program for controlling each means of the bit rate control device according to any one of configurations 1 to 13 by a computer.

[0126] In order to realize part or all of the control in the above-described embodiments, a computer program that realizes the functions of the above-described embodiments may be supplied to a bit rate control device or the like via a network or various storage media. Then, a computer (or a CPU, MPU, or the like) in the bit rate control device or the like may read and execute the program. In this case, the program and the storage medium storing the program constitute the present invention. [Explanation of symbols]

[0127] 100···Camera 200···Switcher 214: Communication statistics acquisition unit 215: Configuration information acquisition unit 216: Bit rate control section 217: Bit rate determination unit 1000: Camera System

Claims

1. a statistical information acquisition means for acquiring statistical information relating to communication on the network; configuration information acquiring means for acquiring tally information indicating the output status of a plurality of video data; a bit rate determination means for determining an encoding bit rate based on the statistical information and the tally information; a bit rate control means for changing the encoding bit rate to the determined bit rate; A bit rate control device comprising:

2. 2. The bit rate control device according to claim 1, further comprising a plurality of video output devices for outputting the video data.

3. 2. The bit rate control device according to claim 1, further comprising a switcher for switching between the plurality of video data.

4. 2. The bit rate control device according to claim 1, wherein said bit rate determining means allocates a higher bit rate to said video data with a higher priority based on tally information indicating the output states of said plurality of video data.

5. 5. The bit rate control device according to claim 4, wherein said bit rate determining means allocates a higher bit rate to said video data when said tally information indicates that said video data is currently being distributed than to video data that is not currently being distributed.

6. 6. The bit rate control device according to claim 5, wherein said bit rate determining means allocates a higher bit rate to said video data when said tally information indicates that said video data is being distributed than to video data that is waiting to be distributed.

7. 7. The bit rate control device according to claim 6, wherein the bit rate determination means allocates a bit rate to the video data when the tally information indicates that the video data is waiting to be distributed that is equal to or higher than that of video data that is neither being distributed nor waiting to be distributed.

8. 2. The bit rate control device according to claim 1, wherein the statistical information includes at least one of an available bandwidth of the network and the number of retransmitted packets.

9. 9. The bit rate control device according to claim 8, wherein said bit rate determining means controls the change of said bit rate based on a result of comparison between the current total bit rate and said available bandwidth.

10. 10. The bit rate control device according to claim 9, wherein the bit rate determination means changes the bit rate when the current total bit rate becomes larger than the available bandwidth, and sets the bit rate to a predetermined value when the current total bit rate becomes smaller than the available bandwidth.

11. 2. The bit rate control device according to claim 1, wherein the tally information or the statistical information is updated periodically or when a difference of a predetermined value or more occurs in the tally information or the statistical information.

12. a plurality of video output devices that output the plurality of video data; 2. The bit rate control device according to claim 1, further comprising: a switcher for switching between the plurality of video data.

13. 2. The bit rate control device according to claim 1, wherein the tally information indicates an output state of the video output device connected to the network.

14. The bit rate control device according to claim 12, characterized in that the configuration information acquisition means acquires at least one of information indicating the number of the video output devices connected to the switcher, information indicating the total value of the bit rates of the multiple video data, the tally information indicating the output status of the video output devices connected to the network, and information indicating the bit rate for each video data output status determined by the video output device.

15. a statistical information acquisition step of acquiring statistical information regarding network communications; a configuration information acquisition step of acquiring tally information indicating output states of a plurality of video data; a bit rate determination step of determining an encoding bit rate based on the statistical information and the tally information; a bit rate control step of changing the encoding bit rate to the determined bit rate; A bit rate control method comprising:

16. A computer program for controlling each means of the bit rate control device according to any one of claims 1 to 14 by a computer.

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